This invention relates to switchgear housings, and more specifically relates to a novel closure for an access opening in the steel door of a switchgear housing wherein the closure consists entirely of a snap-in molded assemblage.
Metal-clad and metal-enclosed switchgear are well known and usually consist of steel cubicles having steel closure doors for enclosing circuit breakers and other electrical equipment. The circuit breakers which are enclosed in the housing carry operation indicators, counters, racking mechanisms, and the like, and personnel must have access to this equipment.
One prior art method of providing such access is simply to open the steel cubicle door so that the entire interior of the cubicle is exposed. This arrangement has the disadvantage of requiring the user to open a large compartment door while a power circuit breaker is closed if only to read a meter or counter or the like. In addition to the inconvenience of having to open the entire compartment door for this relatively minor task, it is possible that the power circuit breaker will operate while the door is open, thereby exposing the operator to a possibly dangerous condition.
Another known method for making the controls and indicator on the circuit breaker accessible to an operator uses an escutcheon on the movable circuit breaker, where the escutcheon carries all of the necessary indicators and operating controls and protrudes through an opening in the steel compartment door. This arrangement is relatively expensive and, moreover, when the circuit breaker is racked to its disconnected position and is in its most forward position relative to the cubicle, the circuit breaker controls extend beyond the front door and into the aisle space.
Another method which has been used in the past included the use of a rectangular opening in the steel compartment door with a metal front access door with separate clasp and hinge for closing this access opening. With this arrangement, when the access door is open, the opening in the main steel door can present sharp edges and burrs which can be hazardous to personnel. Moreover, the access door of this construction is relatively expensive. Access doors have also been provided of a sliding variety but these are also expensive and the relatively sharp and possibly burred opening in the main steel door is exposed when the access door is open.